Preheat your oven to 200C/400F/Gas mark 6 and line an 8x8 inch square tin with either baking parchment or tin foil.Give yourself a little overhang so you can lift your bars out.
Mix the oats, brown sugar and spices together in a medium-sized mixing bowl. Then pour in the melted butter and mix until everything is evenly coated. Pour 2/3 rds of the mixture into the bottom of your pan and press it down to create an even layer. Pop this in your oven for 5 minutes.
While the base in the oven, quickly prepare the rest of your ingredients.
Take the tin out of the oven and place the apple chunks over the semi-cooked base. Evenly sprinkle the quartered caramels over the apples and sprinkle half of the chocolate chips over the apples as well.
With the remaining third of the oat mixture, crumble it over the top of the filling then sprinkle the remaining chocolate chips over the top of this.
Place the pan in your hot oven and bake for 35 minutes.
Take the pan out of the oven, the caramel will be bubbling. It's important to leave the bars until they have completely cooled down to room temperature. They will be nearly impossible to get out of the pan let alone cut if they are warm. If you can leave them overnight to cool down all the better.
Once cool cut them into either 9 or 12 squares depending on what size you want them.
Stored in an airtight container at room temperature these bars will keep for 5 days and they will keep for at least 7 in the fridge. If you keep them in the fridge allow them to warm a little before serving so the caramel softens a little.